No preliminary patentability search of the United States patent art has been conducted in conjunction with this invention. It is known, however, that the prior art has attempted to solve the problem of core growth and core damage in various ways. U.S. Pat. No. 3,834,764 which issued Sept. 10, 1974 to Claude B. Krekeler for Core Breaking Means concentrated on protecting the mounting means and on providing auxiliary cutting elements to break the cores after said cores were permitted to grow. In other instances trim chains have been employed to bridge the gaps aforementioned. Another known prior art arrangement is to mount a drum with a universal mount so that it could be canted from time to time into the path of what would otherwise be a core formation.
Other prior art workers have taken still different approaches. One of these was to provide a considerable number of bit positions so that the paths of travel of the cutting elements would be as close together as possible whereby to minimize core growth; an example of such an arrangement is taught in U.S. Pat. No. 1,528,546. Other arrangements have included chains wherein some of the bits are arranged in primary cutting positions and others of the bits are located in secondary or lower cutting positions; examples of such chains are taught in U.S. Pat. Nos. 2,832,579 and 3,307,875.
The foregoing prior art approaches have helped the situation but they are not without disadvantages. The prior art has not really eliminated core growth. The machinery or techniques employed have proved to be quite expensive and difficult to maintain. Some of the arrangements, particularly those that call for the number of bit positions to be considerably increased, make the feeding of the driven element into the material being worked difficult and slow.
The present invention eliminates the formation of cores by an arrangement which is relatively simple to install, inexpensive and easily maintained in the field.